Lithium bromide absorption refrigeration system
In a water–lithium bromide absorption refrigeration system, water is the refrigerant and lithium bromide (LiBr) is the absorbent. In the absorber, LiBr absorbs water vapor from the evaporator, forming a LiBr–water solution. This process releases heat and maintains low pressure for continuous cooling.
Table of Contents
Introduction:
This system is typically used in industrial and large commercial applications, where it can provide high levels of cooling with low electrical energy consumption.
Also Read: Vapour absorption refrigeration system working, components, definition
Components:
- Absorber: The absorber is the component that contains the lithium bromide solution, which absorbs water vapor from the refrigerant.
- Generator: The generator is responsible for heating the lithium bromide solution to release the absorbed water vapor.
- Condenser: The condenser cools the hot and high-pressure refrigerant vapor to convert it back into a liquid.
- Evaporator: The evaporator is responsible for absorbing heat from the surrounding environment, which is transferred to the refrigerant in the system.
- Expansion Valve: The expansion valve is used to control the flow rate and pressure of the refrigerant in the system.
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| Lithium Bromide Absorption Refrigeration System Diagram |
Li br absorption refrigeration working flow chart:
Working of Lithium bromide absorption refrigeration system:
- In a Lithium bromide absorption refrigeration system, the refrigerant used is water. The system operates by circulating a mixture of water and lithium bromide through a series of components, as follows:
- The absorbent (lithium bromide solution) is heated in the generator, which causes it to release water vapor.
- The refrigerant (water) is then passed through the absorber, where it absorbs the water vapor from the lithium bromide solution.
- The now-humidified refrigerant vapor is passed through the condenser, where it is cooled and condensed back into a liquid state.
- The liquid refrigerant then passes through the expansion valve, where it is throttled to lower pressure and temperature.
- The cooled and low-pressure refrigerant then passes through the evaporator, where it absorbs heat from the surrounding environment, and the cycle starts over again.
Lithium bromide absorption refrigeration system applications:
- Lithium bromide absorption refrigeration system is typically used in large-scale commercial and industrial applications, such as air conditioning for office buildings, hospitals, and industrial process cooling.
- The system is especially useful in areas where electrical power is limited or unreliable since the system can operate using other forms of energy, such as natural gas, waste heat, or solar energy.
- Lithium bromide absorption refrigeration system is also used in remote locations or in areas where water is scarce, as it can be run on non-potable water sources such as seawater or brackish water
lithium bromide absorption refrigeration system nptel:
Frequently Asked Questions
Why is lithium bromide used in absorption refrigeration systems?
Lithium bromide is highly hygroscopic, meaning it easily absorbs water vapor. This property makes it an ideal absorbent in absorption refrigeration systems that use water as the refrigerant.
What is the working principle of a lithium bromide absorption system?
The system operates by evaporating water under low pressure to produce cooling. The water vapor is absorbed by lithium bromide in the absorber, then separated in the generator using heat, and the cycle repeats continuously.
What are the main components of a LiBr absorption refrigeration system?
The key components are the evaporator, absorber, generator, condenser, solution pump, heat exchanger, and expansion valve.
What type of refrigerant is used in a lithium bromide system?
Water is used as the refrigerant in lithium bromide absorption refrigeration systems.
What are the advantages of a lithium bromide absorption refrigeration system?
It operates quietly, uses heat energy instead of electricity, has fewer moving parts, is environmentally friendly, and can utilize waste heat or solar energy as a source.
What are the limitations of a lithium bromide absorption system?
It can only be used for cooling above 0°C since water is the refrigerant. It also has a lower coefficient of performance (COP) compared to vapor compression systems and requires precise control to prevent crystallization of LiBr.
Where are lithium bromide absorption systems commonly used?
They are widely used in large-scale air-conditioning systems, industrial cooling, and in places where waste heat or steam is readily available, such as power plants and process industries.